THERMODYNAMIC PROPERTIES OF THE CO-W-C SYSTEM
THERMODYNAMIC PROPERTIES OF THE CO-W-C SYSTEM
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DOI：
10.1007/bf02651660
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发表时间：
1989-05-01
期刊：
影响因子：
--
通讯作者：
GUILLERMET, AF
中科院分区：
文献类型：
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作者：
GUILLERMET, AF
用CALPHAD方法计算了Co-W-C体系的热力学性质。Co-C和W-C系统的性质是从最近的分析中获得的，而Co-W系统的性质在本工作的第一部分是评估的。特别地，利用磁吉布斯能的Hillert-Jarl模型，从最近的溶解度数据评价了W对降低面心立方Co(TC)居里温度的影响。我们的评估给出了W对T_c的影响没有早期工作那么明显，但强到足以在面心立方相中产生磁性混溶间隙。提出了一种新的Co-W体系相图，该相图反映了不混溶效应。第二部分对Co-W-C系中的fcc、hcp和bcc相、两种三元碳化物(M12C和M6C)以及液态相的性质进行了评价。本文报道了Co-W-C图的各种等温截面和垂直截面，以及液相线表面的投影。目前的热力学描述令人满意地解释了现有的大部分实验信息。
The thermodynamic properties of the Co-W-C system have been evaluated by using the CALPHAD method. The properties of the Co-C and W-C systems are taken from recent analyses, whereas the properties of the Co-W system are evaluated in the first part of the present work. In particular, the effect of W in decreasing the Curie temperature of fcc Co (Tc) is evaluated from recent solubility data, by using the Hillert-Jarl model for magnetic Gibbs energy. Our evaluation gives a less dramatic effect of W on Tc than according to early work, but strong enough to produce a magnetic miscibility gap in the fcc phase. A new phase diagram for the Co-W system, showing the immiscibility effects, is presented. The properties of the fcc, hcp, and bcc phases, two ternary carbides (M12C and M6C), and the liquid phase in the Co-W-C system are evaluated in the second part. Various isothermal and vertical sections, and a projection of the liquidus surface of the Co-W-C diagram are reported. Most of the experimental information available is satisfactorily accounted for by the present thermodynamic description.